ABSTRACT
Transverse-magnetic (TM) and transverse-electric (TE) pass polarizers based on a silicon-on-insulator platform are studied and analyzed. The proposed structures are CMOS-compatible based on indium tin oxide and zirconium nitride as alternative plasmonic materials. The bi-metallic combination of the plasmonic materials exhibit large coupling between one of the modes (TE or TM) in the silicon core and the surface plasmon mode, while the other mode can propagate with low losses. The numerical simulations for the TE-pass polarizer predict 32.7 dB extinction ratio (ER) and 0.13 dB insertion loss (IL) at a compact device length of 1.5 µm. Additionally, the TM-pass polarizer has 31.5 dB ER and 0.17 dB IL at a device length of 2 µm at an operating wavelength of 1.55 µm.
ABSTRACT
Adipose stem cells (ASCs) have recently emerged as a more viable source for clinical applications, compared to bone-marrow mesenchymal stromal cells (BM-MSCs) because of their abundance and easy access. In this study we evaluated the regenerative potency of ASCs compared to BM-MSCs. Furthermore, we compared the dielectric and electro-kinetic properties of both types of cells using a novel Dielectrophoresis (DEP) microfluidic platform based on a printed circuit board (PCB) technology. Our data show that ASCs were more effective than BM-MSCs in promoting neovascularization in an animal model of hind-limb ischemia. When compared to BM-MSCs, ASCs displayed higher resistance to hypoxia-induced apoptosis, and to oxidative stress-induced senescence, and showed more potent proangiogenic activity. mRNA expression analysis showed that ASCs had a higher expression of Oct4 and VEGF than BM-MSCs. Furthermore, ASCs showed a remarkably higher telomerase activity. Analysis of the electro-kinetic properties showed that ASCs displayed different traveling wave velocity and rotational speed compared to BM-MSCs. Interestingly, ASCs seem to develop an adaptive response when exposed to repeated electric field stimulation. These data provide new insights into the physiology of ASCs, and evidence to their potential superior potency compared to marrow MSCs as a source of stem cells.
